18" X 16" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling sidewall Filter Size - 23

Filter Size - 23

positioning supply and return grills accordingly

including the ability to mount without removing the thermostat when using the ring base

Simplified Installation: Our Radial Damper ensures easy setup

18" X 16" ADJUSTABLE AIR SUPPLY DIFFUSER - HVAC Vent Duct Cover Sidewall or Ceiling sidewall Filter Size - 23+ Product Details Size 18"w X 16"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 19. 875" width X 18" height. High Quality High quality steel construction, no scuff powder coat durable finish, smooth, shiny, scratch resistant, no sharp edges, 2 recessed screw holes on each side with screws included, screws same color as vent cover, easy installation. Adjustable airflow control Adjustable airflow